sunyata [Skt.,=emptiness], one of the main tenets of Mahayana Buddhism, first presented by the Perfection of Wisdom (Prajna-paramita) scriptures (1st cent. B.C. on) and later systematized by the Madhyamika school. Early Buddhist schools of Abhidharma, or scholastic metaphysics, analyzed reality into ultimate entities, or dharmas, arising and ceasing in irreducible moments in time. The Mahayanists reacted against this realistic pluralism by stating that all dharmas are "empty," without self-nature (svabhava) or essence. This was a radical restatement of the central Buddhist teaching of non-self (anatman). It was declared that not only ordinary objects, but the Buddha, nirvana, and also emptiness itself are all "empty." The teaching attempts to eradicate mental attachment and the perception of duality, which, since it is a basis for aversion to bondage in birth-and-death (samsara) and desire for nirvana, may obstruct the bodhisattva's compassionate vow to save all beings before entering nirvana himself. Wisdom (prajna), or direct insight into emptiness, is the sixth perfection (paramita) of a bodhisattva. It is stressed by both Buddhist writers and Western scholars that emptiness is not an entity nor a metaphysical or cosmological absolute, nor is it nothingness or annihilation. "Empty" things are neither existent nor nonexistent, and their true nature is thus called not only emptiness but also suchness (tathata).